Crystallographic electron microscopy

We present a family of techniques for the transmission electron microscope that generate surface zone-axis patterns. These patterns display the variation of the diffracted-beam intensity as a function of the angle of the incident electrons. The conditions of the experiments are those of reflection high-energy electron diffraction at near grazing incidence. The techniques are: surface convergent-beam diffraction, a surface analogue of the Tanaka method and a modified double-rocking scheme. Experimental results are presented for diffraction from surfaces of MgO and MoS₂. We anticipate that surface zone-axis patterns (surface ZAPs) will become established as an important tool for surface characterization, especially when used in conjunction with high-resolution surface imaging and surface energy loss spectroscopy; surface ZAPs may be expected to play, in surface analysis, a role analogous to that played by convergent-beam diffraction in normal transmission electron microscopy.     

Result Merging Technique for Answering XPath Query over XSLT Transformed Data

Caching stores the results of previously answered queries in order to answer succeeding queries faster by reusing these results. We propose two different approaches for using caches of XSLT transformed XML data in order to answer queries. The first approach checks whether or not a current query Q can be directly answered from the result of a previously answered query Qi stored in the cache. The new query is otherwise submitted to the source over the network, the answer of the query is determined, transmitted back to the client, and stored in the cache. The second approach determines only the intersection Q−Qi and integrates the result of Q−-Qi into the previous results in the cache, which requires applying a numbering scheme for the output of the XSLT stylesheet. We show by experimental results that the second approach can significantly speed up the answering time in comparison to the first approach, but is not significantly slower in few worst cases than the second approach.     

Structural sensitivity analysis of flexible multibody systems modeled with the floating frame of reference approach using the adjoint variable method

For the efficient analysis and optimization of flexible multibody systems, gradient information is often required. Next to simple and easy-to-implement finite difference approaches, analytical methods, such as the adjoint variable method, have been developed and are now well established for the sensitivity analysis in multibody dynamics. They allow the computation of exact gradients and require normally less computational effort for large-scale problems. In the current work, we apply the adjoint variable method to flexible multibody systems with kinematic loops, which are modeled using the floating frame of reference formulation. Thereby, in order to solve ordinary differential equations only, the equations of motion are brought into minimal form using coordinate partitioning, and the constraint equations at position and velocity level are incorporated in the adjoint dynamics. For testing and illustrative purposes, the procedure is applied to compute the structural gradient for a flexible piston rod of a slider–crank mechanism.     

On the implication problem for cardinality constraints and functional dependencies

In database design, integrity constraints are used to express database semantics. They specify the way by that the elements of a database are associated to each other. The implication problem asks whether a given set of constraints entails further constraints. In this paper, we study the finite implication problem for cardinality constraints. Our main result is a complete characterization of closed sets of cardinality constraints. Similar results are obtained for constraint sets containing cardinality constraints, but also key and functional dependencies. Moreover, we construct Armstrong databases for these constraint sets, which are of special interest for example-based deduction in database design.     

Steady-state bioavailability and day-to-day variability of a multiple-unit (CR/ZOK) and a single-unit (OROS) delivery system of metoprolol after once-daily dosing

Home blood pressure (BP) monitoring is useful in the clinical management of patients with hypertension and the identification of those with "white-coat" hypertension; i.e. high readings in the clinic but normal BP at home. In the process of evaluating this technique, we compared self-measured home BP with intra-arterial BP. Healthy white men (n = 40) of 20-40 years of age and body weight below 95 kg were recruited by advertising in the local newspaper. Following a standardized procedure, performed within 2-4 weeks of a response to the advertisement, BP was measured by a physician at a clinic screening, by the subject at home (14 readings in 7 days) and finally in the clinic concomitantly intra-arterially and oscillometrically. The correlation coefficient for mean (M) home BP (r = 0.73) and oscillometric BP (r = 0.74) against intra-arterial BP were slightly higher than for screening BP (r = 0.65). However, in plots of the differences for individual MBP between the methods against the average of the methods, it appears that at levels of average MBP above 100 mmHg, screening BP overestimates the BP level, while this was not the case for home BP or oscillometric BP. Thus, by using intra-arterial measurement as standard of comparison, subject self-measured home BP is a reliable method of estimating blood pressure level in young men. Home BP measured shortly after screening and recruitment provides useful information of resting BP in subjects who potentially may have initial anxiety about BP measurement.     

Stress Versus Coarticulation: Toward an Integrated Approach to Explicit Speech Segmentation.

Although word stress has been hailed as a powerful speech-segmentation cue, the results of 5 cross-modal fragment priming experiments revealed limitations to stress-based segmentation. Specifically, the stress pattern of auditory primes failed to have any effect on the lexical decision latencies to related visual targets. A determining factor was whether the onset of the prime was coarticulated with the preceding speech fragment. Uncoarticulated (i.e., concatenated) primes facilitated priming. Coarticulated ones did not. However, when the primes were presented in a background of noise, the pattern of results reversed, and a strong stress effect emerged: Stress-initial primes caused more pruning than non-initial-stress primes, regardless of the coarticulatory cues. The results underscore the role of coarticulation in the segmentation of clear speech and that of stress in impoverished listening conditions. More generally, they call for an integrated and signal-contingent approach to speech segmentation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Classification of malnutrition by statistical analysis of quantitative two-dimensional gel electrophoresis of plasma proteins

An attempt to use the relative concentrations of major plasma proteins for clinical assessment of severe malnutrition is described. Quantitative two-dimensional gel electrophoresis was used to measure the concentrations of 24 major proteins in small aliquots of plasma obtained from children, aged 0 to 3 years, who were patients and outpatients in Liberian hospitals. Fifteen had a clinical diagnosis of kwashiorkor, 36 were diagnosed with marasmus, and 18 were controls. There were also 5 controls from the United States. The individuals were placed in six groups; kwashiorkor, kwashiorkor who died during treatment, marasmus, marasmus who died, Liberian controls, and U.S. controls. The amount of protein in each spot in the two-dimensional gels was estimated by measuring bound stain using a laser scanner and computerized image analysis. We found very low serum transferrin levels in malnourishment, in agreement with reports from other investigators. All of the data for 24 protein variables were pooled for factor analysis; the mean factor scores for each group differed, with the kwashiorkor groups furthest from the controls. Results of discriminant analysis using the amounts of different numbers of protein variables (3 to 24) were compared for posterior assignment of individuals to groups. The validity of the method was tested by analysis of plasma aliquots obtained from patients following initiation of therapy and which were not a part of the training set. Predictive performance (prognosis of patient survival) depended upon the number of protein variables used. Although artifactual fitting of the data is expected to contribute to performance as the number of variables is increased, use of as many as 7 variables may be justified, even with our small patient groups. Possible use of these results for development of a practical clinical test is discussed.